Up until your kids reach a certain age, there's a sort of unspoken rule about playdates. They are all mommy and me. As in at least two moms and two kids hanging out just so your kid can get in their social life. Which is all well and good if you have a bunch of mom friends in your 'hood who you love. But then there are those moms, the ones who make accepting a mommy and me playdate with a new family seem like a bigger risk than letting your 6-year-old pick your outfit for the day.

Yes, it's true. I have turned down playdates because I hate the moms more than the kids. But if you saw the list of ladies I'm talking about, here's betting you'd say no too:

1. The One Who Riles Up the Kids: She walks in, spies the kids, and makes a beeline for them. After first whipping a roll of Smarties out of her pocket and passing them around, she then proceeds to get them all worked into a frenzy before finally coming to settle by you. Yeah, thanks a lot. I really needed my dog to spend the rest of the week peeing behind the couch out of utter fear that those two wild 6-year-olds might still be in the living room.

2. The Kids Should Be Seen And Not Heard Mom: Almost as bad as the "makes 'em nuts" mom is the one who brings her kid over, and then throws a hissy when my kid dares come to check in with me because her time with me is being lost. Sorry lady, but unless you come out of my lady parts, you're never going to rate above my kid.

3. The Bragger: It is perfectly acceptable to mention in passing that your smarty pants was nominated to the gifted and talented program. When kids do great things, no one is going to appreciate it quite like another mom. But there's a difference between sharing and rubbing one's nose in it. Not sure where the line is? If your 5-year-old is whipping up his own Hollandaise sauce and bringing you breakfast in bed on a tray with a flower in a jelly jar, please refrain from sharing or you won't be getting an invite back. If I needed someone to make me feel like my life sucks, I'd open a fashion magazine.

4. The Smoker: Sorry, I don't care if you only do it outside. You're not bringing that stank around me or my kid.

5. The Judgearoo: It starts with a running commentary on the toys my daughter brings out of her playroom for her buds to play with. "We would never buy Precious something pink and plastic, we prefer all, natural, wooden dolls that require imagination," she says. Then we settle the kids around my dining room table for lunch, and she proceeds to critique each item procured from my kitchen for the kids to eat. "Cheddar bunnies, really? You know they're still junk even if they're organic," she says.

And finally, the mom who really kills a playdate plan like no one else:

6. The Weirdo: Pretty broad category, I know, and as someone who wholeheartedly embraces her lack of "normalcy," I almost feel bad saying it. But sometimes there are people you just can't bring yourself to hang out with. They're so unlike you that it's painful. Maybe they're really low class, and you shudder to see them around your kids. Maybe they're racist and mean. Or maybe they are just so different from you that you cannot even hold a conversation for 5 seconds.

Since pushing a person out of me, I've learned the universe loves to throw two women together because they have kids . . . as if that's enough. But having a kid didn't change me that much. There are are still some people who just aren't my cup of tea!

How about you? Are there moms who you have found are just impossible to hang out with, no matter how much your kids get along?